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Edmontosaurus
Edmontosaurus was a large hadrosaur from the late Cretaceous Period. It lived in North America alongside dinosaurs such as Tyrannosaurus, Edmontonia, Pachyrhinosaurus, Ornithomimus, Pachycephalosaurus, Albertosaurus, and Triceratops. Information Edmontosaurus were incredibly large hadrosaurs, one of largest in North America. Depending on the species, a fully grown adult could have been 9 meters long, and some of the larger specimens reached the range of 12 meters to 13 meters long. Its weight was on the order of 4 tonnes. Traditionally, E. regalis has been regarded as the largest species, though this was challenged by the hypothesis that the larger hadrosaurid Anatotitan copei is a synonym of Edmontosaurus annectens, as put forward by Jack Horner and colleagues in 2004, and supported in studies by Campione and Evens in 2009 and 2011. The first fossils named Edmontosaurus were discovered in southern Alberta (named after Edmonton, the capital city), in the Horseshoe Canyon Formation (formerly called the lower Edmonton Formation). The type species, E. regalis, was named by Lawrence Lambe in 1917, although several other species that are now classified in Edmontosaurus were named earlier. The best known of these is E. annectens, named by Othniel Charles Marsh in 1892; originally as a species of Claosaurus, known for many years as a species of Trachodon, and later as Anatosaurus annectens. Anatosaurus and Anatotitan are now generally regarded as synonyms of Edmontosaurus annectens. Edmontosaurus was widely distributed across western North America. The distribution of Edmontosaurus fossils suggests that it preferred coasts and coastal plains. It was a herbivore that could move on both two legs and four. Because it is known from several bone beds, Edmontosaurus is thought to have lived in groups, and may have been migratory as well. The wealth of fossils has allowed researchers to study its paleobiology in detail, including its brain, how it may have fed, and its injuries and pathologies, such as evidence for tyrannosaur attacks on a few edmontosaur specimens. As a hadrosaurid, Edmontosaurus was a large terrestrial herbivore. Its teeth were continually replaced and packed into dental batteries that contained hundreds of teeth, only a relative handful of which were in use at any time. It used its broad beak to cut loose food, perhaps by cropping, or by closing the jaws in a clamshell-like manner over twigs and branches and then stripping off the more nutritious leaves and shoots. Because the tooth rows are deeply indented from the outside of the jaws, and because of other anatomical details, it is inferred that Edmontosaurus and most other ornithischians had cheek-like structures, muscular or non-muscular. The function of the cheeks was to retain food in the mouth since it would have to chew and would not swallow like other dinosaurs. The animal's feeding range would have been from ground level to around 4 metrers above. Multiple specimens of Edmontosaurus annectens have been found with preserved skin impressions. Several have been well-publicized, such as the "Trachodon mummy" of the early 20th century, and the specimen nicknamed "Dakota", the latter apparently including remnant organic compounds from the skin, as well as crude coloer pattern preservation, in the form of a striped pattern in the arm's joints. Because of these finds, the scalation of Edmontosaurus annectens is known for most areas of the body. Skin impressions are less well known for E. regalis, but some well-preserved examples have been studied, including one which preserves a soft tissue crest or wattle on the head. It is unknown whether such a crest was present on E. annectens, and whether it was an indicator of sexual dimorphism. Like other hadrosaurids, Edmontosaurus is thought to have been a facultative biped, meaning that it mostly moved on four legs, but could adopt a bipedal stance when needed. It probably went on all fours when standing still or moving slowly, and switched to using the hind legs alone when moving more rapidly. Research conducted by computer modeling in 2007 suggests that Edmontosaurus could run at high speeds, perhaps up to 45 kilometers per hour. Further simulations using a subadult specimen estimated as weighing 715 kilograms when alive produced a model that could run or hop bipedally, use a trot, pace, or single foot symmetric quadrupedal gait, or move at a gallop. The researchers found to their surprise that the fastest gait was kangaroo-like hopping with a maximum simulated speed of 17.3 meters per second (62 kilometers per hour), which they regarded as unlikely based on the size of the animal and lack of hopping footprints in the fossil record, and instead interpreted the result as indicative of an inaccuracy in their simulation. The fastest non-hopping gaits were galloping with a maximum simulated speed of 15.7 meters per second (57 kilometers per hour) and running bipedally with a maximum simulated speed of 14.0 meters per second (50 kilometers per hour). They found weak support for bipedal running as the most likely option for high-speed movement, but did not rule out high-speed quadrupedal movement. While long thought to have been aquatic or semiaquatic, hadrosaurids were not as well-suited for swimming as other dinosaurs (particularly theropods, who were once thought to have been unable to pursue hadrosaurids into water). Hadrosaurids had slim hands with short fingers, making their forelimbs ineffective for propulsion, and the tail was also not useful for propulsion because of the ossified tendons that increased its rigidity, and the poorly developed attachment points for muscles that would have moved the tail from side to side. In-Game Edmontosaurus will be in the early access of Prehistoric Kingdom. 3 species are depicted in the game as different skins, E. reglis, E. annectens, and "E. kuupikensis". Gallery EdmontosaurusOntogeny.jpg|''Edmontosaurus'' ontogeny 1jmaCDu.jpg BSSiYiT.png o23ZUbL.png S7SYsNS.jpg 5K0z0v1.jpg Edmontosaurus_01_Preview.png|Graveled/''E. regalis'' Edmontosaurus_02_Preview.png|Vibrant/''E. annectens'' Edmontosaurus_03_Preview.png|Arctic/"E. kuukpikensis" 2a-620x349.png Category:Dinosaurs Category:Herbivore Category:Ornithopod